Inclusive quarkonium production at forward rapidity in pp collisions at √s = 8 TeV

We report on the inclusive production cross sec- tions of J/ψ , ψ (2S), Υ (1S), Υ (2S) and Υ (3S), measured at forward rapidity with the ALICE detector in pp colli- sions at a center-of-mass energy √s = 8 TeV. The analy- sis is based on data collected at the LHC and corresponds to an integrated luminosity of 1.23 pb−1. Quarkonia are reconstructed in the dimuon-decay channel. The differen- tial production cross sections are measured as a function of the transverse momentum pT and rapidity y, over the pT ranges0< pT <20GeV/cforJ/ψ,0< pT <12GeV/c for all other resonances, and for 2.5 < y < 4. The cross sections, integrated over pT and y, and assuming unpo- larized quarkonia, are σJ/ψ = 8.98 ± 0.04 ± 0.82 μb, σψ(2S) =1.23±0.08±0.22μb,σΥ(1S) =71±6±7nb, σΥ(2S) =26±5±4nbandσΥ(3S) =9±4±1nb, where the first uncertainty is statistical and the second one is systematic. These values agree, within at most 1.4σ , with measurements performed by the LHCb collaboration in the same rapidity range.